1. Field
Methods and apparatuses consistent with exemplary embodiments relate to testing semiconductor memory devices and, more particularly, to a semiconductor memory device testing method by which an optimum operating condition for a semiconductor memory device in a wafer state is extracted.
2. Description of Related Art
Semiconductor memory devices are divided into volatile memory devices and non-volatile memory devices according to whether or not stored data is lost when power supply to the device is interrupted. Operation modes of non-volatile memory devices are divided into a write mode or program mode in which data is stored in memory cells, a read mode in which data is read from memory cells, and an erase mode in which stored data is erased from memory cells. These operational characteristics and other various characteristics such as characteristics of manufacturing processes and structural characteristics need to be considered when developing non-volatile memory devices for efficiently storing data.
In manufacturing non-volatile memory devices, tests are performed during a wafer stage in order to understand optimum operating conditions. When taking various operating conditions into account, tests are usually performed depending on an engineer's know how since the number of tests is restricted. As a result, there is a disadvantage in that it is highly likely that operating conditions other than operating conditions that are actually optimum are chosen as optimum conditions.